WP Automatic plugin can import Tiktok videos from a specific user or hashtag, it checks the latest 15 posts by default but if you want to import older items, here is how to

1- Visit the profile or tag page

2- Scroll as many times as desired to show the videos you want to import

3- Right Click on any empty part and inspect element

4- Move to the HTML element on the top, right click and copy element

5- paste it to the campaign, save and run